248.The answer is d.(Young, pp 341, 359. Junqueira, pp 449, 459, 463–464.
Kierszenbaum, p 582.)The low (4.0) pH of the vagina is maintained by bac-
terial metabolism of glycogen to form lactic acid. The vagina is character-
ized by a stratified squamous epithelium that contains large accumulations
of glycogen. Glycogen is released into the vaginal lumen and is subse-
quently metabolized to lactic acid by commensal lactobacilli. The low pH
inhibits growth of a variety of microorganisms, but not sexually transmit-
ted pathogens, such as Trichomonas vaginalis. Treatment for vaginal infec-
tions usually includes acidified carriers to reestablish a more acidic pH like
that usually seen in mid-menstrual cycle.
380 Anatomy, Histology, and Cell Biology
(Reproduced, with permission, from Kasper DL, et al (eds.). Harrison’s Principles of Internal
Medicine, 16th ed. New York, NY: McGraw-Hill, 2005: 2201.)